In recent years, an electronic key system, such as a smart entry system, has a portable wireless key to perform a control pertaining to locking and unlocking of a vehicle door lock. In such a portable wireless key, many rubber knobs are employed for purposes of design and waterproof, for example, as disclosed in a patent literature 1. On and off operations of switches by operating the knobs are usually conducted by push-type switches. The size of the push-type switches has been reduced with a size reduction of the portable wireless key. In the portable wireless key reduced in size, however, a user feels a movable projection of the push-type switch with his or her finger in a pressing operation, and thus an operational feeling is likely to deteriorate.